Long-term evolution of broken wakefields in finite radius plasmas

A novel effect of fast heating and charging a finite-radius plasma is discovered in the context of plasma wakefield acceleration. As the plasma wave breaks, the most of its energy is transferred to plasma electrons which create strong charge-separation electric field and azimuthal magnetic field around the plasma. The slowly varying field structure is preserved for hundreds of wakefield periods and contains (together with hot electrons) up to 80% of the initial wakefield energy.Comment: 5 pages, 6 figure

Numerical Studies of Electron Acceleration Behind Self-Modulating Proton Beam in Plasma with a Density Gradient

Presently available high-energy proton beams in circular accelerators carry enough momentum to accelerate high-intensity electron and positron beams to the TeV energy scale over several hundred meters of the plasma with a density of about 1e15 1/cm^3. However, the plasma wavelength at this density is 100-1000 times shorter than the typical longitudinal size of the high-energy proton beam. Therefore the self-modulation instability (SMI) of a long (~10 cm) proton beam in the plasma should be used to create the train of micro-bunches which would then drive the plasma wake resonantly. Changing the plasma density profile offers a simple way to control the development of the SMI and the acceleration of particles during this process. We present simulations of the possible use of a plasma density gradient as a way to control the acceleration of the electron beam during the development of the SMI of a 400 GeV proton beam in a 10 m long plasma. This work is done in the context of the AWAKE project --- the proof-of-principle experiment on proton driven plasma wakefield acceleration at CERN.Comment: 4 pages, 5 figures

Proton Beam Defocusing as a Result of Self-Modulation in Plasma

The AWAKE experiment will use a \SI{400}{GeV/c} proton beam with a longitudinal bunch length of $\sigma_z = 12\,\rm{cm}$ to create and sustain GV/m plasma wakefields over 10 meters . A 12 cm long bunch can only drive strong wakefields in a plasma with $n_{pe} = 7 \times 10^{14}\,\rm{electrons/cm}^3$ after the self-modulation instability (SMI) developed and microbunches formed, spaced at the plasma wavelength. The fields present during SMI focus and defocus the protons in the transverse plane \cite{SMI}. We show that by inserting two imaging screens downstream the plasma, we can measure the maximum defocusing angle of the defocused protons for plasma densities above $n_{pe} = 5 \times 10^{14}\,\rm{electrons/cm}^{-3}$. Measuring maximum defocusing angles around 1 mrad indirectly proves that SMI developed successfully and that GV/m plasma wakefields were created. In this paper we present numerical studies on how and when the wakefields defocus protons in plasma, the expected measurement results of the two screen diagnostics and the physics we can deduce from it.Comment: 3 pages, 2 figures, Conference Proceedings of NAPAC 201

The mRubyFT Protein, Genetically Encoded Blue-to-Red Fluorescent Timer.

peer reviewedGenetically encoded monomeric blue-to-red fluorescent timers (mFTs) change their fluorescent color over time. mCherry-derived mFTs were used for the tracking of the protein age, visualization of the protein trafficking, and labeling of engram cells. However, the brightness of the blue and red forms of mFTs are 2-3- and 5-7-fold dimmer compared to the brightness of the enhanced green fluorescent protein (EGFP). To address this limitation, we developed a blue-to-red fluorescent timer, named mRubyFT, derived from the bright mRuby2 red fluorescent protein. The blue form of mRubyFT reached its maximum at 5.7 h and completely transformed into the red form that had a maturation half-time of 15 h. Blue and red forms of purified mRubyFT were 4.1-fold brighter and 1.3-fold dimmer than the respective forms of the mCherry-derived Fast-FT timer in vitro. When expressed in mammalian cells, both forms of mRubyFT were 1.3-fold brighter than the respective forms of Fast-FT. The violet light-induced blue-to-red photoconversion was 4.2-fold less efficient in the case of mRubyFT timer compared to the same photoconversion of the Fast-FT timer. The timer behavior of mRubyFT was confirmed in mammalian cells. The monomeric properties of mRubyFT allowed the labeling and confocal imaging of cytoskeleton proteins in live mammalian cells. The X-ray structure of the red form of mRubyFT at 1.5 Å resolution was obtained and analyzed. The role of the residues from the chromophore surrounding was studied using site-directed mutagenesis

Стрілецька зброя та вогнева підготовка

Підручник містить рекомендації щодо вивчення озброєння підрозділів, його практичного застосування під час навчання студентів за програмою підготовки офіцерів запасу для наземної артилерії РВ і А Сухопутних військ. У виданні врахований досвід науково-педагогічних працівників кафедри військової підготовки СумДУ, військової практики. Книга актуальна для опрацювання під час навчання й службової діяльності. Рекомендований студентам, науково-педагогічним працівникам кафедри військової підготовки СумДУ

Chronicles of nature calendar, a long-term and large-scale multitaxon database on phenology

We present an extensive, large-scale, long-term and multitaxon database on phenological and climatic variation, involving 506,186 observation dates acquired in 471 localities in Russian Federation, Ukraine, Uzbekistan, Belarus and Kyrgyzstan. The data cover the period 1890-2018, with 96% of the data being from 1960 onwards. The database is rich in plants, birds and climatic events, but also includes insects, amphibians, reptiles and fungi. The database includes multiple events per species, such as the onset days of leaf unfolding and leaf fall for plants, and the days for first spring and last autumn occurrences for birds. The data were acquired using standardized methods by permanent staff of national parks and nature reserves (87% of the data) and members of a phenological observation network (13% of the data). The database is valuable for exploring how species respond in their phenology to climate change. Large-scale analyses of spatial variation in phenological response can help to better predict the consequences of species and community responses to climate change.Peer reviewe

Remote photoplethysmography application to the analysis of time-frequency changes of human heart rate variability

In this article we present the possibilities of using remote photoplethysmography (rPPG or imaging PPG) technology to estimate time-frequency changes of human heart rate variability. We propose improvements for algorithm presented in our recent study. Algorithm modification allows to exclude skin areas with highly variable levels of lighting, thus reducing noise level and increasing duration of signal suitable for processing. Twenty healthy volunteers (males and females) aged from 20 to 25 took part in this investigation. The blood volume pulse rate estimated from the rPPG rhythmogram and cardiac pulse rate estimated from the electrocardiogram are compared. The results showed that the very low frequency hemodynamic oscillations of blood volume pulse rate estimated from the rPPG rhythmogram in the [0.04-0.003] Hz frequency band can be used to monitor functional changes of a human

Features of Creation of Surface Layer Mechanical Condition Parameters in Orthogonal Cutting

In this article, the technique and research results on creation of surface layer mechanical conditions parameters at orthogonal cutting are presented. Stress tensor, strain rate tensor and general mechanical condition factors distribution along flow lines were obtained. Distributions of stresses, strain rates, mean normal stress and stress state index along flow lines consist of three steps of quasi-monotonous deformation. On every step there is a monotonous increasing or decreasing of these parameters. It is demonstrated that creation of surface layer mechanical condition parameters in metal cutting and surface plastic deformation methods follow common patterns. Experimental research results confirmed the validity of proposed analytical models for stressing programs in orthogonal metal cutting

Electron Injection Studies for the AWAKE Experiment at CERN

The AWAKE experiment recently approved at CERN will use the self-modulation instability (SMI) of long (12 cm), relativistic (400 GeV/c) proton bunches in dense plasmas to drive wakefields with accelerating gradients at the GV/m level. These accelerating gradients will be probed by externally injected electrons. In order to preserve the plasma uniformity required for the SMI the first experiments will use on-axis injection of a low energy 10-20 MeV electron beam collinearly with the proton beam. In this article we describe the physics of electron injection into the proton driven SMI wakefields. Requirements on the injected electron beam are determined and the final accelerated beam parameters are obtained via numerical simulations

Results of the telephone survey on quitting smoking in Ukraine

Andreeva, T. I., Petrenko, T., & Krasovsky, K. S. (2016). Results of the telephone survey on quitting smoking in Ukraine. Survey report